Combined fixed-angle square and protractor



A. H. HELDEN. comsmen FIXED ANGLE SQUARE AND PHOTRACTOR. APPLICATIONFILED FEB. 28, 1919. 1,365,991, Patented Jan, 18, 1921.

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34, a ("IMAM/M01 woe/nap A. H. HELDEN. COMBINED FIXED ANGLE SQUARE ANDPROTRACTOR.

APPLICATION FILED FEB'. 28, I919.

Patented Jan. 18, 1921.

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Mow M1 0 A. H. HELDEN. COMBINED FIXED ANGLE SQUARE AND PROTRACTOR.APPLICATION F|LED fEB.28,19l9.

1,365,991, Patented Jan. 18, 1921.

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Gum/W 0 PATENT OFFICE.

ALFRED HELDEN, OF KANSAS CITY, MISSOURI.

COMBINED FIXED-ANGLE SQUARE AND PRO'IRAGT'OR.

Specification of Letters Patent.

Application filed February 28, 1919. Serial No. 279,689.

To all whom it may concern:

Be it known that I ALFRED H. HELDEN, a citizen of the United tates,residing at Kansas City, in the county of Jackson and State of Missouri,have invented certain new and useful Improvements in Combined F ixed-Angle Squares and Protractors; and I do doclare the following to be afull, clear, and exact description of the invention, such as will enableothers skilled in the art to which it appertains to make and use thesame.

This invention relates togeometrical instruments, and it relates morespecifically to an improved combined fixed-angle square and protractor.One object of the invention is to provide a device of this characterwhich is extremely convenient and thoroughly practical for laying offangles on rafters, braces, stairs, etc.

A further object is to provide an adjustable device of this characterwith which the angles of both thetop .and bottom cuts of a rafter may belaid off while the adjustment of its parts remains unchanged. 1

Another object is to provide a device of this character whichsimultaneously indicates the degree of angularity and the pitch or risein inches per foot.

Another object is to provide a device of this character which comprisesa square having an improved fraction-index thereon to coact with thebase in indicating the fractional pitch of one line relative to anotherline.

Other objects and advantages may become apparent to persons who read theollowing details of description in connection with the accompanyingdrawings, in which:

Figure 1 is a side elevation showing my improved geographical instrumentapplied to a beam which is to be laid off and scribed.

Fig. 2 is an enlarged front elevation of the device, the blade andwingof the square being broken off. i I

Fig. 3 is an enlarged rear elevation of the device, except being shownwiththe square in a different position from that shownin Fi .2.

ig. 4 is a sectional view along the line 4-4 of Fig. 2.

Fig. 5 is a sectional view along the line 5--5 of Fig. 2.

Fig. 6 is a sectional view along the line 6-6 of Fig. 2.

Fig. ,7 is a detail view illustrating the angular element or squaredetached from the base of the device.

Referring to these drawings in detail, in which similar referencecharacters correspond with similar parts throughout the several views,the device broadly consists of a base 10, an angular element or square11, and a pivot 12 which unites the square with the base. The basepreferably consists of two plates 13 and 14 which are L-shaped in crosssection, and a flat plate 15, the latter being embraced between theplates 13 and 14, and these three parts are secured together by rivets16 or by other appropriate means. Each of the members 18 and 14 isprovided with a flange which extends from end to end thereof, and thesurfaces 17 of these flanges are straight and disposed in the sameplane.

Each of these surfaces 17 constitutes a working face of the base memberas will be seen by reference to Fig.1. The bar or plate 15 is formedwith a semi-circular recess 18 around which is a segmental or arcuatescale 19, and each of the members 13 and 14 is formed with an apertureor bearing 20 which is concentric with the arcuate scale 19. Onesegmental portion of the scale 19 is provided with graduations andnumerals to indicate degrees of angularity, as shown at 21,another'portion of the scale being graduated and numbered to indicateunits of linear measure, inches being indicated in the present instance,as shown at 22.

Thesquare or angular element 11 has its outer edges 23 and 24 parallelwith the corresponding inner edges 25 and 26, and the outer edges, ifproduced, would pass through the center of the segmental scale 19, thiscenter being spaced from the working faces 17 a distance equal to thedistance between the edges 23 and 25 of the square. The inner edge 27 ofthe plate 15 is also spaced from the working faces 17 a distance equalto the distance between the edges 23 and 25, so that when the edge 23 isagainst the edge 27, the edge 25 is flush with the working faces 17, andthe edge 24 is at right angles to the length of the faces 17, as hereshown in Fig. 3.

The angular element 11 is formed with an index element 28 which extendsoutwardly therefrom and terminates in two indexing points or indicatingpointers 29 and 30. The index 28 is disposed within the semi-circularrecess or aperture 18, and each Patented Jan. 18, 1921. i

indexing point is in alinement with one of the outer edges 2324:, theother indexing point being in alinement with the other one of said outeredges. The pivot 12 extends through an aperture 31 at the apex of theangle formed by producing the edges 23-24, and the center of thisaperture is directly between the point 29 and the edge 2 f, being alsodirectly between the point 30 and edge 23. It will be seen, therefore,that when the instrument is adjusted as shown in Fig. 3, the indexingpoint 30 registers with a point on the scale which may be properlytermed the zero point of the arcuate 0r segmental graduation 21.However, this zero point for the edge 26 is also the point for the edges23 and 25, that is, as shown in Fig. 3, when the indexing point 30registers with the mark at the beginning of the scale or graduation 21,it indicates that the edge 26 is flush or parallel with the workingfaces 17 and that the edges 23 and 25 are at right angles thereto; but,when the indexing point 30 is moved upward along the scale 21 itindicates the degree of angularity between the working surfaces 17 andthe edges 24 and 26. Although I have spoken of the index or graduation21 in the singular, it will be seen, by referring to Figs. 2 and 3, thatthe scale 21 is duplicated on opposite sides of the plate 15, and thesame is true regarding the scale 22. Referring now more specifically tothe scale or graduation 22, it is seen that the same is arranged forindicating the amount of pitch as referred to the surfaces 17 and theedges 23 and 25. In other words, this scale indicates the number ofinches rise for each foot of run along a beam to be laid off. Althoughthis scale indicates but 18 inches of rise, it will be seen that thescale may be increased to 24: inches rise, if desired, withoutconflicting with or overlapping the scale 21.

The square is provided with outwardly I diverging lines 32 which coactwith the working faces 17, in a well known manner, for indicating thefractional pitch, thus pitch, 1]; pitch, pitch, etc., as indicated at33. In order to avoid confusion of the fractions 33, with the lines 32which are not intended to be designated by these fractions, the latterare placed in a column at a distance from the terminals of the lines 32,and curved lines 34 connect the respective fractions with the lines 32intended to be designated, respectively, thereby.

The pivot 12 is preferably in the form of a screw, and a wing nut 34 isprovided on the screw and cooperates therewith and with the somewhatyieldable bars 1.3 and 14c for effecting a clamping or frictionalengagement with the opposite sides of the square, so that the latter maybe held thereby in its respective adjustments. Y From the foregoingdisclosure of the construction and operation of the device, it will beseen that this device is useful in many relations and for many purposes,including the laying off of beams according to angular measure, oraccording to a pitch in inches per foot, or according to f actionalpitch. This enables a person to use the device, without the necessity ofresorting to mathematics where the pitch is given in degrees 0 l'angular measure, or in inches per foot. or in fractions.

In order that the utility of this device may be extended still further,a spirit level 35 is provided, the index elements of this level beingarranged to register when the surfaces 17 are level. By this means, thedevice may be employed for ascertaining whether a beam or surface isplumb, level. or inclined at any angle, the degree of inclination beingdete mined by the cooperation of this level with the indexing points andother features of the instrument.

Although I have described this embodiment of my invention veryspecifically, it is not intended to limit this invention to these exactdetails of construction and arrangement of parts, but I am entitled tomake changes within the scope of the inventive ideas disclosed in theforegoing description and following claims.

What I claim as my invention is:

1. In a geometrical instrument, a base provided with a working face anda segmental scale having its center spaced from said face, an elementhaving straight-edged blades fixed at an angle to each other, thiselement being pivoted at the intersection of the outer edges of saidblades to said base at the center of said segmental scale, said elementhaving an indicating pointer in alinement with one of said edges andmovable over said scale.

2. The structure defined by claim 1., and a second indicating pointer inalinement with another one of said edges which is at an angle to thefirst said one of the edges, said scale comprising separate sets ofgraduations that coact with said edges respectively.

3. The structure defined by claim 2, one of said sets of graduationsconsisting of units of length, the other of said set-s consisting ofunits of angular measure.

4. The structure defined by claim 3, one of said sets of graduationsincluding a zero on a line that intersects said working face at rightangles and also intersects the pivotal axis of said adjustable element.said base and adjustable element being provided with means to confinemovement of one of said indicating pointers within the arcuate limits ofits set of graduations.

5. In a geometrical instrument, a base provided with a working face anda segmental scale, and an adjustable element iiicluding two outer edgesfixed at right angles to one another and two inner edges parallel withsaid outer edges respectively, said adjustable element also comprisingan indicating pointer in alinement with one of said outer edges, saidadjustable element being pivotally connected to said base at a point atthe center of curvature of said scale, said center being spaced fromsaid Working face a distance equal to the distance between two of theparallel edges of said adjustable element so that the inner one of thesetwo edges is flush with said working face when the outer one of theother two parallel edges is at right angles to said working face, saidscale having a zero in the position to register with said indicatingpointer when the last mentioned outer one of these edges is at rightangles to said Working face.

In testimony whereof I have hereunto set my hand.

ALFRED H. HELDEN.

